中国农业科学Issue(1)：63-72,10.DOI:10.3864/j.issn.0578-1752.2015.01.07
柑橘黄龙病菌侵染对甜橙叶片糖代谢的影响
Effect of Candidatus Liberibacter asiaticus Infection on Carbohydrate Metabolism in Citrus sinensis
摘要
Abstract
[Objective]The objective of this experiment is to study the effect of Huanglongbing (HLB) infection on carbohydrate metabolism in Citrus sinensis, elucidate the relationship between HLB infection and starch accumulation, and provide a theoretical basis for HLB pathogenesis. [Method]C. sinensis were used as the experimental materials, plants were inoculated by grafting three bark pieces onto the rootstock portion of each plant. For infected plants, bark pieces were derived from trees infected with Candidatus Liberibacter asiaticus, which were confirmed positive for Ca. L. asiaticus by PCR. For non-infected plants, bark pieces were obtained from healthy trees. Three plants in good growth state were chosen for successive test, mature leaves were collected every month until October. DNA and RNA were extracted, the content of soluble sugar and starch were measured immediately, the other leaf tissue was snap-frozen with liquid nitrogen and stored at -80℃ for testing carbohydrate metabolism related key enzyme activities. At the same time, the expression levels were compared using real-time quantitative PCR analysis.[Result]The content of soluble sugar and starch tended to increase with time extended, and their peak value were respectively reached 1.59 and 3.73 times of control in June, then slightly decreased later, the ratio of soluble sugar to starch dropped down. Various key enzymes imposed different hands on carbohydrate metabolism at different stages of infection. Sucrose phosphate synthase activity rapidly rose to the top 58.44 μg·g-1·min-1 and had become lower than control in late infection; acid invertase had been consistently high and the difference was significant (P<0.05), the highest activity was 2.91 times of control at middle stage; the activity of neutral invertase was kept at a lower level and had the same change trend in experimental group and control group; soluble starch synthase activity was closely related to granule-bond starch synthase, coordinating the synthesis of acting on the starch, while amylase activity had dropped to some extend at each stage, even as low as 0.38 U·g-1 at middle stage. Real-time quantitative PCR indicated that there was a significant relationship between the expression level of sucrose phosphate synthase and its enzyme activity (P<0.05). Among the sucrose decomposition related genes, sucrose synthase gene was not changed obviously and had lower change range while cell wall-bound invertase gene CSCWI was up-regulated with the highest value of about 7.4 times and expressed abundantly during the whole process. Starch decomposition-related genes BAM3, MEX1 and DPE2 had a relatively reduced expression and the difference was significant (P<0.05) in different periods.[Conclusion]HLB infection has influence on the formation and transportation of photosynthate in C. sinensis and results in the disruption of carbohydrate metabolism balance, it is in deep connection with starch accumulation and the late stage symptoms.关键词
甜橙/柑橘黄龙病/柑橘黄龙病菌/糖代谢/淀粉积累Key words
Citrus sinensis/citrus Huanglongbing/Candidatus Liberibacter asiaticus/carbohydrate metabolism/starch accumulation引用本文复制引用
吴越,苏华楠,黄爱军,周彦,李中安,刘金香,周常勇..柑橘黄龙病菌侵染对甜橙叶片糖代谢的影响[J].中国农业科学,2015,(1):63-72,10.基金项目
国家公益性行业（农业）科研专项 （）
